a grocery merchandiser from cincinnati, ohio... a student of art history from san diego, california... and our returning champion, a research chemist originally from charlotte, north carolina... and now here is the host of "jeopardy!" -- alex trebek! thank you, johnny. . ladies and gentlemen, welcome keith, our returning champion, has had as impressive a debut on "jeopardy!" as anyone in recent memory, averaging more than $25,000 per victory. so, tori and meredith, you've got your work cut out for you today. let's see what happens. they'll pick up the signaling devices because we're going to work right now in the jeopardy! round, which has one daily double that will appear in one of these categories.